Air cooling and liquid cooling are used for cooling electronic devices such as servers. The liquid cooling is a method of cooling electronic devices using the evaporation heat and the sensible heat of coolant, and is capable of cooling the electronic devices more efficiently than the air cooling.
In the liquid cooling system, pumps are provided for circulating coolant in the electronic device. When there is only one pump in the system, the circulation of the coolant is stopped when the pump breaks down, resulting in the situation where the electronic device cannot be cooled. To prevent such a situation, it is effective to provide a plurality of pumps to make the pumps redundant so that even when one of the pumps fails, the other pumps can keep circulating the coolant.
However, the system of the redundant pumps still has room of improvement in increasing the flow rate of the circulating coolant.
Note that techniques related to this application are disclosed in Japanese Laid-open Patent Publications Nos. 2005-315255, 2007-103470, and 2005-228237.